[container.gen.reqmts] Adjust subclause names and stable tags

There are no more cross-references to [container.gen.reqmts] or
[container.requirements.general], so this doesn't affect anything else.

Author: jwakely

source/containers.tex

@@ -69,12 +69,12 @@
 aligned buffers and call \tcode{construct} to place the element into the buffer.
 \end{note}
 
-\rSec2[container.gen.reqmts]{General containers}
+\rSec2[container.requirements.general]{General containers}
 
-\rSec3[container.requirements.general]{General}
+\rSec3[container.intro.reqmts]{Introduction}
 
 \pnum
-In subclause \ref{container.gen.reqmts},
+In subclause \ref{container.requirements.general},
 \begin{itemize}
 \item
 \tcode{X} denotes a container class containing objects of type \tcode{T},
@@ -103,7 +103,7 @@
   ranges::@\libconcept{input_range}@<R> && @\libconcept{convertible_to}@<ranges::range_reference_t<R>, T>;
 \end{codeblock}
 
-\rSec3[container.reqmts]{Containers}
+\rSec3[container.reqmts]{Container requirements}
 
 % Local command to index names as members of all containers.
 \newcommand{\indexcont}[1]{%

source/xrefdelta.tex

@@ -30,6 +30,9 @@
 %   \movedxrefiii{old.label}{new.label.1}{new.label.2}{new.label.3}
 %   \movedxrefs{old.label}{new place (e.g., \tref{blah})}
 
+% https://github.com/cplusplus/draft/pull/6255
+\movedxref{container.gen.reqmts}{container.requirements.general}
+
 %%% Deprecated features.
 %%% Example:
 %